Those threads are not getting locked for avoiding repetitive threads and you have done that one exactly. If those threads get locked, one has to create new thread for discussing on a specific topics.
We, as members who often read, must warn them that their posts have been discussed.
Of course, try to look at old strands, many don't work anymore, they even repeat them, and lots of threads that don't have quality. It looks like it needs to be locked if it doesn't work, reduces spam, and if it's not locked, it will cause many posts that are less qualified. Only a suggestion.